without social media its not possible to connect new collaborators and known person in field, and once the collaboration is started it should be closely carried vial email .
Both can be used such as here in RG, which is a social media platform for scientists and other researchers: for promoting and discussing their research: https://blogs.lse.ac.uk/impactofsocialsciences/2013/07/26/a-to-z-of-social-media-for-academia/
Which is a better media for interacting among colloborators during the colloborative research -Social media or Email ?
Depending nature of the research i.e. how extensive the collaboration is required as well as at which stage of the collaboration. E.g. if the nature of the research required extensive brainstorming, follow-through / up, high urgency, adhoc idea generation & clarification are required etc., perhaps social media is better approach etc. If it is towards an end stage or stabilized stage of a collaborative research that just need to consolidate certain documentations or only periodical update, then email can be a better approach.